A G via llvm-dev
2021-Jun-08 04:14 UTC
[llvm-dev] Compiling linux with `clang -fbasic-block-sections=labels`
Hi, I'm trying to build the linux kernel with *`clang -fbasic-block-sections=labels`.* I ran into this error: /tmp/main-81886d.s: Assembler messages: /tmp/main-81886d.s: Error: .size expression for .BB.set_reset_devices does not evaluate to a constant /tmp/main-81886d.s: Error: .size expression for .BB.debug_kernel does not evaluate to a constant /tmp/main-81886d.s: Error: .size expression for .BB.quiet_kernel does not evaluate to a constant /tmp/main-81886d.s: Error: .size expression for .BB.loglevel does not evaluate to a constant make kernelversion 5.10.0 clang version 11.1.0 (g... at github.com:llvm/llvm-project.git 1fdec59bffc11ae37eb51a1b9869f0696bfd5312) Target: x86_64-unknown-linux-gnu 1. Can someone help me understand what this error means? 2. Is *clang-built-linux* a better place to ask this question? 3. Is there a workaround for this? Thanks Akshith -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210607/186e97cd/attachment.html>
David Blaikie via llvm-dev
2021-Jun-08 05:39 UTC
[llvm-dev] Compiling linux with `clang -fbasic-block-sections=labels`
BB sections has only been tested/implemented with a fairly narrow set of flags so far as I know, and is sufficiently novel that various features won't interact correctly with it without some work to support the combination of bb sections and those features. I'd /guess/ BPF, for instance, probably doesn't work with BB sections out of the box & may require some work (like some work was needed to support BB sections with DWARF) - I believe BPF is mandatory/used by default when building the Linux kernel? So maybe that's what's being tripped over here. But could something else entirely - that's just my first guess. On Mon, Jun 7, 2021 at 9:15 PM A G via llvm-dev <llvm-dev at lists.llvm.org> wrote:> Hi, > I'm trying to build the linux kernel with *`clang > -fbasic-block-sections=labels`.* > > I ran into this error: > > /tmp/main-81886d.s: Assembler messages: > /tmp/main-81886d.s: Error: .size expression for .BB.set_reset_devices does > not evaluate to a constant > /tmp/main-81886d.s: Error: .size expression for .BB.debug_kernel does not > evaluate to a constant > /tmp/main-81886d.s: Error: .size expression for .BB.quiet_kernel does not > evaluate to a constant > /tmp/main-81886d.s: Error: .size expression for .BB.loglevel does not > evaluate to a constant > > make kernelversion > 5.10.0 > > clang version 11.1.0 (g... at github.com:llvm/llvm-project.git > 1fdec59bffc11ae37eb51a1b9869f0696bfd5312) > Target: x86_64-unknown-linux-gnu > > > 1. Can someone help me understand what this error means? > 2. Is *clang-built-linux* a better place to ask this question? > 3. Is there a workaround for this? > > Thanks > Akshith > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210607/c799b44e/attachment.html>